Electro-wetting display panel

ABSTRACT

An electro-wetting display panel including an active device array substrate, a dielectric layer, a wall structure, a first liquid containing dyes, a second liquid, and an opposite substrate is provided. The active device array substrate includes a substrate, scan lines, data lines, and pixels. The pixels are electrically connected with the scan lines and the data lines accordingly. Each pixel includes an active device, a transparent pixel electrode, and a reflective layer. The transparent pixel electrode located above the reflective layer is electrically connected with the active device. The reflective layer has a bumpy surface. The dielectric layer is disposed on the active device array substrate. The wall structure is disposed on the dielectric layer. The first liquid is disposed on the dielectric layer. The opposite substrate is disposed above the active device array substrate. The second liquid is disposed between the active device array substrate and the opposite substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan applicationserial no. 98142945, filed on Dec. 15, 2009. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a reflective flat panel display. Moreparticularly, the present invention relates to an electro-wettingdisplay panel.

2. Description of Related Art

With great advance of electronic paper (E-paper) and electronic book(E-book), the display device with features of light, thin and flexiblebecomes the major development trend. Most of the current E-papers areimplemented with the use of the electrophoresis techniques. Also, mostof the E-papers and the E-books are equipped with reflective displaydevices. That is, the E-papers and the E-books can display images byreflecting the external light source.

Taking the electro-wetting display panel as an exemplar, in order toreflect the external light source so that the user can successfully tosee the image, the reflective layer is one of the dispensable componentsin the electro-wetting display panel, as disclosed in US PatentPublication No. 2007/0127108. In the aforementioned Patent Publication,the reflective surface of the reflective layer is a flat reflectivesurface. However, the reflectivity of the reflective layer having theflat reflective surface is quite low in normal operation. Hence, how toimprove the reflectivity of the electro-wetting display panel becomesone of the key techniques for manufacturing the electro-wetting displaypanel.

Besides, the response speed of the electro-wetting display panel dependson the moving speed of the liquid in the electro-wetting display panel.Thus, how to speed up the moving speed of the liquid in theelectro-wetting display panel also becomes one of the key techniques formanufacturing the electro-wetting display panel.

SUMMARY OF THE INVENTION

The present invention provides an electro-wetting display panel in whichthe design of the pixel electrode can quickly drive the first liquidcontaining dyes to move or increase the area of the opening.

The present invention provides an electro-wetting display panel havingan active device array substrate, a dielectric layer, a wall structure,a first liquid containing dyes, a second liquid and an oppositesubstrate. The active device array substrate comprises a substrate, aplurality of scan lines, a plurality of data lines and a plurality ofpixels. Each of the pixels is electrically connected with one of thescan lines and one of the data lines correspondingly, and each of thepixels comprises an active device, a transparent pixel electrode and areflective layer. The transparent pixel electrode is electricallyconnected with the active device and is located above the reflectivelayer, and the reflective layer has a bumpy surface. The dielectriclayer is disposed on the active device array substrate, and the wallstructure is disposed on the dielectric layer, and the first liquidcontaining dyes is disposed on the dielectric layer. Moreover, theopposite substrate is disposed over the active device array substrateand the second liquid is located between the opposite substrate and theactive device array substrate.

The present invention further provides an electro-wetting display panelhaving an active device array substrate, a dielectric layer, a wallstructure, a first liquid containing dyes, a second liquid and anopposite substrate. The active device array substrate comprises asubstrate, a plurality of scan lines, a plurality of data lines and aplurality of pixels. Each of the pixels is electrically connected withone of the scan lines and one of the data lines correspondingly, andeach of the pixels comprises an active device, a transparent pixelelectrode and a reflective layer. The transparent pixel electrode iselectrically connected with the active device and is located above thereflective layer, and the reflective layer has a bumpy surface. Also, atleast a portion of the bumpy surface is arranged without being coveredby the transparent pixel electrode. The dielectric layer is disposed onthe active device array substrate, and the wall structure is disposed onthe dielectric layer, and the first liquid containing dyes is disposedon the dielectric layer. Moreover, the opposite substrate is disposedover the active device array substrate and the second liquid is locatedbetween the opposite substrate and the active device array substrate.

According to one embodiment of the present invention, the active devicearray substrate includes a thin film transistor array substrate.Further, the aforementioned active devices include amorphous siliconthin film transistors or polysilicon thin film transistors.

According to one embodiment of the present invention, the active devicearray substrate further comprises an inter-dielectric layer, a pluralityof bumps and a planar layer. The inter-dielectric layer covers theactive devices, and the bumps are disposed on the inter-dielectriclayer, and the reflective layer is disposed on the inter-dielectriclayer to cover the bumps. The planar layer is disposed on theinter-dielectric layer to cover the reflective layer, and thetransparent pixel electrodes are disposed on the planar layer, and thedielectric layer is disposed on the planar layer to cover thetransparent pixel electrodes.

According to one embodiment of the present invention, the each of thetransparent pixel electrodes has at least an opening to expose at leasta portion of the bumpy surface. Moreover, the aforementioned opening canbe, for example, a stripe opening, a round opening or a ring opening.

According to one embodiment of the present invention, the oppositesubstrate includes a common electrode and a black matrix layer.

According to one embodiment of the present invention, the pixels includereflective pixels or transflective pixels.

According to one embodiment of the present invention, the dielectriclayer has a hydrophobic surface, the wall structure is hydrophilic, thefirst liquid containing dyes is a non-polar liquid, and the secondliquid is a polar conductive liquid.

According to one embodiment of the present invention, the dielectriclayer has a hydrophilic surface, the wall structure is hydrophobic, thefirst liquid containing dyes is a conductive polar liquid, and thesecond liquid is a non-polar liquid.

Since the reflective layer in the electro-wetting display panel of thepresent invention has a bumpy surface, one embodiment of the presentinvention is capable of improving the reflectivity of theelectro-wetting display panel to obtain a relatively better displayquality. Moreover, one of the embodiments of the present invention canspeed up the response speed of the electro-wetting display panel by welldesigning the pixel electrode.

In order to make the aforementioned and other features and advantages ofthe invention more comprehensible, embodiments accompanying figures aredescribed in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 and FIG. 1′ are respectively a schematic top view and a schematiccross-sectional view of a single pixel in an electro-wetting displaypanel according to one embodiment of the present invention.

FIGS. 2A through 2F are schematic top views showing a method formanufacturing an electro-wetting display panel according to oneembodiment of the present invention.

FIGS. 2A′ through 2F′ are schematic cross-sectional views showing amethod for manufacturing an electro-wetting display panel according toone embodiment of the present invention.

FIG. 3 and FIG. 3′ are respectively a schematic top view and a schematiccross-sectional view of a single pixel in an electro-wetting displaypanel according to another embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

FIG. 1 and FIG. 1′ are respectively a schematic top view and a schematiccross-sectional view of a single pixel in an electro-wetting displaypanel according to one embodiment of the present invention. Further,FIG. 1′ is a schematic cross-sectional view along a line X-X′ in FIG. 1.

As shown in FIG. 1 and FIG. 1′, an electro-wetting display panel 100 ofthe present embodiment comprises an active device array substrate 110, adielectric layer 120, a wall structure 130, a first liquid 140containing dyes, a second liquid 150 and an opposite substrate 160. Theactive device array substrate 110 comprises a substrate 112, a pluralityof scan lines 114, a plurality of data lines 116 and a plurality ofpixels 118. Each of the pixels 118 is electrically connected with one ofthe scan lines 114 and one of the data lines 116 correspondingly, andeach of the pixels 118 comprises an active device TFT, a transparentpixel electrode P and a reflective layer R. The transparent pixelelectrode P is electrically connected with the active device TFT and islocated above the reflective layer R, and the reflective layer R has abumpy surface B. The dielectric layer 120 is disposed on the activedevice array substrate 110, and the wall structure 130 is disposed onthe dielectric layer 120, and the first liquid 140 containing dyes isdisposed on the dielectric layer 120. Moreover, the opposite substrate160 is disposed over the active device array substrate 110 and thesecond liquid 150 is located between the opposite substrate 160 and theactive device array substrate 110. Further, the second liquid 150 islocated on the first liquid 140 containing dyes. In one embodiment ofthe present invention, at least a portion of the bumpy surface B is notcovered by the transparent pixel electrode P.

The active device array substrate 110 can be, for example, a thin filmtransistor array substrate. The active devices TFT on the thin filmtransistor array substrate can be, for example, amorphous silicon thinfilm transistors or polysilicon thin film transistors. That is, theactive device array substrate 110 can be a polysilicon thin filmtransistor array substrate (such as the substrate mentioned in thepresent embodiment) or an amorphous silicon thin film transistor arraysubstrate (not shown).

Taking the polysilicon thin film transistor array substrate of thepresent embodiment as an exemplar, except for the substrate 112, thescan lines 114, the data lines 116 and the pixels 118, the active devicearray substrate 110 further comprises an inter-dielectric layer 111, aplurality of bumps 113 and a planar layer 115. The inter-dielectriclayer 111 covers the active devices TFT, and the bumps 113 are disposedon the inter-dielectric layer 111, and the reflective layer R isdisposed on the inter-dielectric layer 111 to cover the bumps 113. Theplanar layer 115 is disposed on the inter-dielectric layer 111 to coverthe reflective layer R, and the transparent pixel electrodes P aredisposed on the planar layer 115, and the dielectric layer 120 isdisposed on the planar layer 115 to cover the transparent pixelelectrodes P.

In the present embodiment, the each of the transparent pixel electrodesP has at least an opening AP to expose at least a portion of the bumpysurface B. In addition, according to the designing requirements ofdifferent products, the opening AP can be, for example, a stripeopening, a round opening, a ring opening or other opening with asuitable shape. It should be noticed that, in the present embodiment,the opening AP of the transparent pixel electrode P is, in general, theregion with the reflective layer arranged thereunder and without beingcovered by the transparent pixel electrode P.

In the present embodiment, the opposite substrate 160 includes a commonelectrode 162 and a black matrix layer 164. For instance, the commonelectrode 162 and the black matrix layer 164 of the opposite substrate160 can be, for example, disposed on a substrate 166, and the commonelectrode 162 can, for example, cover the black matrix layer 164.

In the electro-wetting display panel 100 of the present embodiment, thesurface of the dielectric layer 120 can be treated to be a surface 120 awith the hydrophobic characteristic or the hydrophilic characteristic.The hydrophilic-hydrophobic characteristics of the dielectric layer 120and the wall structure 130 are different from each other. When thesurface of the dielectric layer 120 is hydrophobic, the wall structure130 should be designed to be hydrophilic and the first liquid 140containing dyes should be the non-polar liquid (such as decane andsilicon oil) and the second liquid 150 can be, for example, water orother polar liquid. Alternatively, when the surface of the dielectriclayer 120 is hydrophilic, the wall structure 130 should be designed tobe hydrophobic and the first liquid 140 containing dyes should be thepolar conductive liquid and the second liquid 150 should be thenon-polar liquid.

FIGS. 2A through 2F are schematic top views showing a method formanufacturing an electro-wetting display panel according to oneembodiment of the present invention. FIGS. 2A′ through 2F′ are schematiccross-sectional views showing a method for manufacturing anelectro-wetting display panel according to one embodiment of the presentinvention.

As shown in FIG. 2A and FIG. 2A′, a patterned polysilicon layer PL isformed on a substrate 112. The patterned polysilicon layer PL can be,for example, formed by low-temperature polysilicon process (LTPSprocess), ion doping process and patterning process. The low-temperaturepolysilicon process can be, for example, the excimer laser annealingprocess. In detail, the patterned polysilicon layer PL can be dividedinto a channel region CH, a source doped region S, a drain doped regionD and a storage capacitor region C. After the patterned polysiliconlayer PL is formed, a gate insulating layer GI is formed on thesubstrate 112 to cover the patterned polysilicon layer PL.

As shown in FIG. 2B and FIG. 2B′, after the gate insulating layer GI isformed, the scan lines 114 and a plurality of common lines Com areformed on the gate insulating layer GI. The scan lines 114 which overlapthe channel region CH is regarded as gates. It is known from FIG. 2B andFIG. 2B′, the gate, the channel region CH, the source doped region S andthe drain doped region D together form an active device TFT having threeterminals. Further, the storage capacitor region C, the common lines Comand the gate insulating layer GI located between the storage capacitorregion C and the common lines Com together form a storage capacitor Cst.After the common lines Com and the scan lines 114 are formed, theinter-dielectric layer 111 is formed on the gate insulating layer GI tocover the common lines Com and the scan lines 114.

As shown in FIG. 2C and FIG. 2C′, a plurality of contact windows W1 areformed in the inter-dielectric layer 111 and the gate insulating layerGI to expose the source doped region S and the drain doped region D.

As shown in FIG. 2D and FIG. 2D′, after the contact windows W1 areformed, the data lines 116, a plurality of drain connecting linesD_(CT), the bumps 113 and the reflective layer R are formed on theinter-dielectric layer 111. The data lines 116 and the drain connectinglines D_(CT), are electrically connected with the source doped region Sand the drain doped region D respectively. The drain connecting linesD_(CT) is electrically connected with the drain doped region D throughthe contact windows W1. For instance, the data lines 116 and the drainconnecting lines D_(CT) can be formed by one patterning process, and thereflective layer R can be formed by another patterning process.Alternatively, all of the reflective layer R, the data lines 116 and thedrain connecting lines D_(CT) can be formed by the same patterningprocess. It should be noticed that, before the reflective layer R isformed, the bumps 113 with predetermined height and distribution densityare formed on the inter-dielectric layer 111. Hence, the later formedreflective layer R which is conformal to the bumps 113 possesses arelatively high reflectivity.

As shown in FIG. 2E and FIG. 2E′, after the data lines 116, the drainconnecting lines D_(CT), the bumps 113 and the reflective layer R areformed, the planar layer 115 is formed to cover the data lines 116, thedrain connecting lines D_(CT), the bumps 113 and the reflective layer R.It is known from FIG. 2E and FIG. 2E′, the planar layer 115 has acontact window W2 to expose a portion of the drain connecting linesD_(CT). Then, the transparent pixel electrode P is formed on the planarlayer 115. The transparent pixel electrode P is electrically connectedwith the drain connecting lines D_(CT) through the contact window W2. Itshould be noticed that, after the transparent pixel electrode P isformed, the fabrication of the active device array substrate 110 iscompleted.

After the transparent pixel electrode P is formed, the dielectric layer120 is formed on the planar layer 115 to cover the transparent pixelelectrode P. Noticeably, the surface of the dielectric layer 120 can bea hydrophobic surface or a hydrophilic surface.

As shown in FIG. 2F and FIG. 2F′, after the dielectric layer 120 isformed, the wall structure 130 is formed on the surface of thedielectric layer 120. The wall structure 130 is used to define thelocations of the pixels 118. When the surface of the dielectric layer120 is the hydrophobic surface, the wall structure 130 should bedesigned to be hydrophilic. Alternatively, when the surface of thedielectric layer 120 is the hydrophilic surface, the wall structure 130should be designed to be hydrophobic.

After the process steps shown in FIGS. 2A through 2F and FIGS. 2A′through 2F′ are performed, the active device array substrate 110 havingthe dielectric layer 120 and the wall structure 130 disposed thereon isassembled with the opposite substrate 160 in a face-to-face manner.Further, the first liquid 140 containing dyes and the second liquid 150are formed between the active device array substrate 110 and theopposite substrate 160. Hence, the fabrication of the electro-wettingdisplay panel 100 is completed.

FIG. 3 and FIG. 3′ are respectively a schematic top view and a schematiccross-sectional view of a single pixel in an electro-wetting displaypanel according to another embodiment of the present invention. Further,FIG. 3′ is a schematic cross-sectional view along a line Y-Y′ in FIG. 3.The electro-wetting display panel 100′ of the present embodiment issimilar to the electro-wetting display panel 100. The difference betweenthe electro-wetting display panel 100′ and the electro-wetting displaypanel 100 is that the bumps 113 and the reflective layer R in theelectro-wetting display panel 100′ do not distribute all over thedisplay region. That is, the bumps 113 and the reflective layer R in theelectro-wetting display panel 100′ only distribute on a portion of thedisplay region. In other words, the electro-wetting display panel 100′is a transflective-type electro-wetting display panel, and theelectro-wetting display panel 100 shown in FIG. 1 is a reflective-typeelectro-wetting display panel.

Since the reflective layer in the electro-wetting display panel of thepresent embodiment has a bumpy surface, the present embodiment iscapable of improving the reflectivity of the electro-wetting displaypanel to obtain a relatively better display quality. Moreover, portionsof the embodiments of the present invention can speed up the responsespeed of the electro-wetting display panel by designing the pixelelectrode.

1. An electro-wetting display panel comprising: an active device arraysubstrate, comprising: a substrate; a plurality of scan lines; aplurality of data lines; and a plurality of pixels, wherein: each of thepixels is electrically connected with one of the scan lines and one ofthe data lines correspondingly; each of the pixels comprises an activedevice, a transparent pixel electrode and a reflective layer; thetransparent pixel electrode is electrically connected with the activedevice and is located above the reflective layer; and the reflectivelayer has a bumpy surface; a dielectric layer disposed on the activedevice array substrate; a wall structure disposed on the dielectriclayer or the active device array substrate; a first liquid containingdyes, the first liquid containing dyes being disposed on the dielectriclayer; a second liquid; and an opposite substrate disposed over theactive device array substrate, wherein the second liquid is locatedbetween the opposite substrate and the active device array substrate. 2.The electro-wetting display panel of claim 1, wherein the active devicearray substrate includes a thin film transistor array substrate.
 3. Theelectro-wetting display panel of claim 2, wherein the active devicesinclude amorphous silicon thin film transistors or polysilicon thin filmtransistors.
 4. The electro-wetting display panel of claim 1, whereinthe active device array substrate further comprises: an inter-dielectriclayer covering the active devices; a plurality of bumps disposed on theinter-dielectric layer, wherein the reflective layer is disposed on theinter-dielectric layer to cover the bumps; and a planar layer disposedon the inter-dielectric layer to cover the reflective layer, wherein thetransparent pixel electrodes are disposed on the planar layer and thedielectric layer is disposed on the planar layer to cover thetransparent pixel electrodes.
 5. The electro-wetting display panel ofclaim 1, wherein the each of the transparent pixel electrodes has atleast an opening to expose at least a portion of the bumpy surface. 6.The electro-wetting display panel of claim 1, wherein the oppositesubstrate comprises a common electrode and a black matrix layer.
 7. Theelectro-wetting display panel of claim 1, wherein the pixels includereflective pixels or transflective pixels.
 8. The electro-wettingdisplay panel of claim 1, wherein the dielectric layer has a hydrophobicsurface, the wall structure is hydrophilic, the first liquid containingdyes is a non-polar liquid, and the second liquid is a polar conductiveliquid.
 9. The electro-wetting display panel of claim 1, wherein thedielectric layer has a hydrophilic surface, the wall structure ishydrophobic, the first liquid containing dyes is a polar conductiveliquid, and the second liquid is a non-polar liquid.
 10. Anelectro-wetting display panel comprising: an active device arraysubstrate, comprising: a substrate; a plurality of scan lines; aplurality of data lines; a plurality of pixels, wherein: each of thepixels is electrically connected with one of the scan lines and one ofthe data lines correspondingly; each of the pixels comprises an activedevice, a transparent pixel electrode and a reflective layer, thetransparent pixel electrode is electrically connected with the activedevice and is located above the reflective layer; the reflective layerhas a bumpy surface; and at least a portion of the bumpy surface isarranged without being covered by the transparent pixel electrode; adielectric layer disposed on the active device array substrate; a wallstructure disposed on the dielectric layer; a first liquid containingdyes disposed on the dielectric layer; a second liquid; and an oppositesubstrate disposed over the active device array substrate, wherein thesecond liquid is located between the opposite substrate and the activedevice array substrate.
 11. The electro-wetting display panel of claim10, wherein the dielectric layer has a hydrophobic surface, the wallstructure is hydrophilic, the first liquid containing dyes is anon-polar liquid, and the second liquid is a polar conductive liquid.12. The electro-wetting display panel of claim 10, wherein thedielectric layer has a hydrophilic surface, the wall structure ishydrophobic, the first liquid containing dyes is a polar conductiveliquid, and the second liquid is a non-polar liquid.
 13. Theelectro-wetting display panel of claim 10, wherein the each of thetransparent pixel electrodes has at least an opening to expose at leasta portion of the bumpy surface.
 14. The electro-wetting display panel ofclaim 10, wherein the pixels include reflective pixels or transflectivepixels.
 15. (canceled)